Device for cutting endless material, for example for the production of staples from synthetic fibers

ABSTRACT

A device for cutting endless fibrous material, particularly for the production of staples from synthetic fibers, which comprises a rotatably disposed support means feeding the fibrous material to a cutting zone, said support means being operatively associated with a rotatably mounted cutting means and comprising drum means subjected to a suction draft.

United States Patent 1191 Fleissner DEVICE FOR CU'I'I'ING ENDLESS MATERIAL, FOR EXAMPLE FOR THE PRODUCTION OF STAPLES FROM SYNTHETIC FIBERS Hans Fleissner, Frankfurt am Main, Germany Assignee: Vepa AG, Riehen/Basel, Switzerland Filed: Apr. 24, 1972 Appl. No.: 246,659

Inventor:

[30] Foreign Application Priority Data Apr. 23, 1971 Germany 2119821 Dec. 1, 1971 Germany 2159485 Feb. 10, 1972 Germany 2206255 83/356.3, 83/411 R, 83/422, 83/913 1111.0 .,.D01g 1/04 Field 61 Search 83/913, 98-100,

References Cited UNITED STATES PATENTS 8/1938 Joa 83/152 X US. Cl 83/100, 83/310, 83/340, 7

FOREIGN PATENTS OR APPLICATIONS 639,466 6/1950 Great Britain 83/98 1,087,317 8/1960 Germany 83/913 Primary ExaminerJ. M. Meister Attorney, Agent, or Firm-Craig & Antonelli [57] ABSTRACT A device for cutting endless fibrous material, particularly for the production of staples from synthetic fibers, which comprises a rotatably disposed support means feeding the fibrous material to a cutting zone, said support means being operatively associated with a rotatably mounted cutting means and comprising drum means subjected to a suction draft.

41 Claims, 17 Drawing Figures PATENI LU Am: 2? 7 mm SHEET 10F 4 Pmumwa 3.83-1.473

SHEH 205 Q PATENIED we 2 7 m4 SHEET 3 OF 4 Fig.1!

DEVICE FOR CUTTING ENDLESS MATERIAL, FOR EXAMPLE FOR THE PRODUCTION OF STAPLES FROM SYNTHETIC FIBERS vided by pressure against the blade. Both systems are burdened by disadvantages.

In the beating procedure, each blade is propelled transversely through a cable held between gear wheels, or the cable travels along the periphery of a rubber roll, against which a knife roller rotates; radially projecting knife blades of this knife roller beat against the. cable and separate the cable under pressure. In this system, the tool life of the knives, in particular, are short; furthermore, the staple lengths obtained are nonuniform.

The crushing of the fibers is a more advantageous method for producing simple fibers. In this method, the cable is wound up spirally on a knife cage. From the outside, a solely pressure-producing roll contacts the wound-up cable package at a constant spacing with respect to the axis of the knife cage. Once the cable layer, applied in spiral windings to the knife cage, has reached a certain thickness, the pressure between the roll and the radially aligned knife blades of the knife cage will reach a strength sufficient to separate the fiber layers pressed directly against the blades of the cage. Here, the service life of the blades is considerably longer, because the fibers do not come into contact with the counter roll. Yet, alone from the viewpoint of the principle involved, this separating method is undersirable, because very high pressures are required in order to obtain the cutting of the fibers, which pressures impair the blade.

The best mode of cutting always is dependent on the movement of the blade relatively to the material to be cut. In case of a handsaw and a knife, the motion is reciprocating; this, however, is unsuitable for a continuous operation, It is therefore desirable to move the blade continuously with respect to the material which is to be cut transversely.

A further problem, which in certain cases is even more complicated, resides in holding the cable during the cutting operation. It is conventional to hold the cable by means of the teeth of two opposed gear wheels. It is also possible to retain the cable on a counter roll during the cutting operation by means of a contact roll rotating approximately coaxially with the knife cage. However, none of these possibilities as yet represents a desirable and final solution. Consequently, this invention is furthermore directed to means for holding the cable during a cutting operation which exerts a maximum amount of friction.

mounted element as .a sieve drum means which is .under a suction draft. This sievedrum meanscanhave ashell which is perforated or otherwise suitablyaconstructed to be air-permeable. In any event, bymeans of the suction draft generated within thedrum by a fan arranged, for example, at the front'face, the long, but still very thin cable will flatly contact the sieve drum shell and will be firmly retained thereon, so. that a bladeican be guided without difficulties through the fixedly held cable.

This blade, as further required by this invention, to be guided relatively to the cable at a highspee'd, if possible. For this purpose, the axes of the sieve drum and of a rotatable cutting blade, disposed at a spaced distance from each other, are suitably arranged perpendicular with respect to each other, wherebya transverse cut is also made possible'by means of a frictional movement.

A suitable embodiment of the cutting means consists in fashioning this means as a rotating disk provided with one or more blades along its outer circumference. These blades, which. can be constructed to be straight or curved in a convex manner, can'be endless (i.e..continuous) or can also be provided with interruptions. ln case of an endless blade, there isthepossibility of constructing the cutting means as. a worm wheel with one preferably in a rotatable manner, optionally even. in a driven manner. Another possibility resides in aligning the blades, formed, for example, of exchangeable razor blades or the like, in an inclined manner under an angle with respect to the tangent at the mounting point of this blade at the cutting means, so that each blade of. the cutting means executes a cut through the cable for the production of the individual staples.

In thecutting device of this invention, the cable, which is held in a spread-out condition fixedly on the sieve drum, is thus cut in the desired staple length by means of a blade guided through the cable at ahigh speed. In order to prevent the blade from coming into contact with the outer surface of the sieve drum, it is advantageous to provide grooves in'the shell of the sieve drum, which grooves are aligned obliquely with Starting with a device as described in the foregoing,

respect to the axis of the drum and determine the staple length; the blade partially enters these groovesnln this way, the very sensitive blade'does not contact the. sieve .drum shell, so that the service life thereof will be optimal. The .angle of the groovesobliquely to the drum axis depends on the speed ratio of the peripheral speed of the drum and the rotational speed of thecuttingdevice. These speeds vmust be extremely accurately adapted to each other, so that the blade .underno circumstances comes into contact with the outer surface of the drum.

The grooves in the drum shell can be milled into a finished drum. Here, it can evenbe advantageous to fashion the sieve drum shell to beconcave, so that the groove is of the same depth at-all'points over the width of the shell. However, it is alsopossible to-manufacture the sieve drum shell of sheet metal strips, which strips are attached at the end walls at a minor spacing from one another for the formation of the grooves. In any event, the minimum staple length is always determined by the spacing from one groove to the next on the drum periphery. In this connection, the maximum staple length is independent of the number of grooves, since this length is also dependent on the rotational speed of the cutting means; it is possible, for example, to omit one or two of the grooves in the successively conducted cutting steps. Thereby, the staple length can be determined, without exchanging the cutting means and also without exchanging the sieve drum, solely by the velocities of the two rotating parts with respect to each other.

After a staple, at the cutting point, has been separated from the continuously fed band of fibers, the fibers are suitably removed from the sieve drum by an air stream and are conveyed to the subsequent treatment unit. For this conveying step, it is advantageously possible to utilize the air stream produced by the fan to provide the suction draft within the sieve drum. Furthermore, this air stream can also serve for detaching the staple fibers from the sieve drum, by conducting a portion of the conveyed air from the outside against the perforations into the zone of the inner covering or baffle serving for preventing the suction draft along the portion of the shell which is not covered by the cable. This stream is then again blown, from the interior of the sieve drum, to the outside of the drum at the level of the point or zone where the staple fiber is detached from the sieve drum, (after the suction draft has been interrupted by the covering). The air conducted against the fibers at this point can then also serve simultaneously for the further conveying of the fibers.

A prerequisite for obtaining such a satisfactory cutting result is that all fibers are fixedly held at least at the cutting point or zone. Difficulties have been encountered in obtaining this objective in the device. The fibers can be blown about on the drum by the draft of air coming from the direction of the cutting means. Besides, air eddies can form in the zoneof the cutting point, affecting the upper layers of the material transported on the drum.

Consequently, measures must be taken to effectively prevent the blowing about of the fibers at the cutting point, by means of which measures the discharge of the cut staples is simultaneously flawlessly ensured. This objective is attained by providing means which force the endless material to be cut tautly onto the drum in the longitudinal direction and which have an effect on the material at least at the cutting point.

Such means can be of a varying nature. For example, the means can consist of a spring or the like pressing from the outside against the fibrous material and thus against the drum; in this connection, the free end of the spring or the like should extend directly up to the cutting point. Another possibility for solving the problem by the aforementioned means resides in the advantageous utilization of a suction unit removing the cut fibers. This suction unit is provided, according to this embodiment, at the half of the sieve drum not covered by the fibrous material, across from the cutting means. In this embodiment, in contrast to another embodiment according to which the inner drum cover is to begin only at a region behind the cutting point or zone so that the fibers are held on the drum on both sides of the executed cut, the cover in this invention is to be extended up to the level of the cutting point, and a suction nozzle is to be disposed directly on the other side of the rotating cutting device. This makes it possible to hold the end of the cable to be cut, by the one hand, b the drum under a suction draft and, on the other hand, by the suction draft of the suction nozzle, so that the cable is tautly stretched, which is advantageous especially for textured cables.

by means of the suitably very high suctiondraft produced by the suction nozzle, the cable or tow disposed on the sieve drum in a more or less loose condition is tightly tensioned at the cutting point so that the cutting operation, on the one hand, can be carried out across the entire width of the two immediately upon contact of the cutting blade with the fiber, without there being the possibility that individual fibers move together with the blade by the pressure exerted by the blade; and on the other hand, even in case of texturized material, the resultant lengths of the staple fibers are always constant. It has even proved to be advantageous to shield the cutting slot proper against the suction draft by means of the inner cover; this holds true especially in case of short staple fibers, since these would otherwise be conveyed into the sieve drum through the cutting gap or groove.

Among the cutting blades mentioned herein, circular cutting leaves or plates have proven to be advantageous, especially in case these are rotatably mounted, thus making it possible to utilize during the course of the cutting operation the entire circular periphery of the leaves for cutting, until the leaves have become blunt and must be exchanged for new ones. This servicing of the machine, however, makes itnecessary to leave the entire fiber producing a line at a standstill for a relatively long period of time; this should occur only at rare intervals, since it means a loss in productivity.

another disadvantage in this connection is that the cutting leaves do not become blunt suddenly, but rather are worn down gradually so that, until they are exchanged, at least the preceding cutting operations will turn out unsatisfactory in quality. This can be avoided, according to this invention, by associating the blade of the cutting plates with a sharpening mechanism engaging the blade. Due to this measure, the respective cutting leaft or plate will rotate about its axis by a certain amount, on account of the friction of the cutting plates on the two or cable, and thus will offer a new cutting edge to the cable at the next cutting operation. Simultaneously, at another point of the cutting plate, the whetting device or sharpening means of this invention will grind the cutting plates along the periphery consequently, the cutting leaves will always exhibit a uniform sharpness until the leaves have been ground down and have become too small for any further cutting steps. However, each leaf will still exhibit its original sharp cutting edge.

The construction of the arrangement of the sharpening or whetting device with respect to the cutting plates of a cutting disk can be effected in various ways. For example, the sharpening device can be mounted fixedly to the cutting device or movably with respect to the rotating cutting disk. The rotation of the cutting plates can be effected by the aforementioned friction between the plates and the cable, i.e. automatically, or also by means of a separate drive. The same holds true for the movement of the whetting device, which can also be disposed independently of the cutting disk fixedly at a housing surrounding the cutting disk, so that the cutting disk, rotating at a high velocity, has the blades of the cutting leaves in constant frictional engagement with this sharpening device. The surface of the sharpening device can be intermittent or can also be fashioned as a grinding disk. Furthermore, the grinding surface can engage the blade of the cutting plates only on one side-but also on both sides.

The device of this invention will be further understood from the following detailed description of several of its embodiments and by reference to the accompanying drawings, wherein:

FIG. 1 is a sectional view of the cutting device of the invention with a fan housing disposed behind a sieve drum, in anelevational illustration;

FIG. 2 is a section through the device of FIG. 1, taken along line II-II;

FIG. 3 is a top view of the sieve drum shown in FIG. 1 on an enlarged scale;

FIG. 4 is a cross section of one embodiment of the outer shell; of the sieve drum arrangement on an enlarged scale;

FIG. 5 is a cross section of another embodiment of the outer shell of the sieve drum arrangement on an en larged scale,

FIG. 6 shows an embodiment of cutting disks of the device on an enlarged scale;

FIG. 7 shows another embodiment of the cutting disks of the device on an enlarged scale;

FIG. 8 shows still another embodiment of the cutting disk;

FIG. 9 shows yet another embodiment of the cutting disk;

FIG. 10 shows a sectional view of a cutting device similar to that of FIG. 1;

FIG. 11 is a top view of the sieve drum shown in FIG. 10 on an enlarged scale;

FIG. 12 is a section through the drum shown in FIG. 10 in the zone of the cutting point on an enlarged scale;

FIG. 13 is a section through a synthetic fiber tow cutting device identical to that of FIG. 10;

FIG. 14 shows the detail of the cutting device encircled in FIG. 13, on an enlarged scale;

FIG. 15 is an elevational view of the cutting disk with a cutting leaf or plate in an enlarged representation;

FIG. 16 is a section through the cutting disk according to FIG. 15, taken along line XVI-XVI; and

FIG. 17 is a section through the cutting disk according to FIG. 15, taken along line XVII-XVII.

The device for cutting a cable of synthetic fibers, denoted by 1, into staple fibers 2 comprises essentially a sieve drum 3, rotatably mounted on one side in a stand 4 in a driven manner. On the other side of the sieve drum, a fan 5 is likewise rotatably mounted and driven in the center of a stand 6. The fan places the interior of the sieve drum 3 under a suction draft and conveys the air sucked in through the perforations on the peripheral surface of the sieve drum shell 3' via a spirally arranged fan housing 7 into a duct 8.

The duct also serves simultaneously to effect transportation of the staple fibers to or in the direction of the machine disosed after the cutting device.

A cutting disk, denoted by reference numeral 9, is arranged at right angles to the axis of the sieve drum 3;

this cutting disk, with its blade, severs the tow or cable 1 held on the sieve drum 3. The cutting disk 9 is advantageously aligned horizontally, so that the thusproduced staple fibers 2 are discharged from the cutting device solely by their own weight. The cutting disk 9 is likewise rotatably mounted in a housing and is driven at a high rate of speed.

The function of the devices illustrated in FIGS. 1 and 2 is quite simple and clear. The endless cable 1 of synthetic fibers which is conducted to the sieve drum via a spreading device 10 by means of a guide roller 11, is

firmly held on the sieve drum 3 due to the suction draft produced by the fan 5. Once the cable is at the level of the cutting disk 9, the cable is still held by the suction draft on both sides of the out which is takingplace, since the inner cover 12 within the drum for interrupting the suction draft along the sector of the drum surface not covered by the material begins below the cutting point. In this way, a clean cut transversely through the fiber cable is ensured, with the cable being fixedly held on the support surface provided by the drum.

In the illustrated cutting device, the air taken in by the fan 5 through the shell 3 of the sieve drum is not only utilized for retaining the cable 1, but also for the discharge of the cut staple fibers 2. For this purpose, the spiral housing 7 is extended, at its outlet duct-8, into the region where the staple fibers 2 drop from the cutting zone. Furthermore, the exhaust air of the fan 5 is additionally conducted into the space between the cover 12 and the sieve drum outer surface, with the aid of a baffle 16, in order to blow any staple fibers adhering to the sieve drum away from the shell surface by an air stream (shown by arrows). This air stream then likewise serves for the further transporting of the staple fibers 2.

As can be seen from FIG. 3, the sieve drum 3 is provided with grooves 13 on its perforated drum shell 3'; the blade of the cutting disk 9, during its movement transversely through the cable 1, penetrates into these grooves with its edge. In this way, the blade does not come into contact with the surface of the sieve drum; this has a particularly advantageous affect on the service life of the blade. The grooves 13 in the sieve drum surface must be aligned obliquely with respect to the axis of the sieve drum, because the sieve drum continues its rotation during the cutting step. The extent of this obliqueness depends on the relationship between the speeds of rotation of the cutting disk 9 and the sieve drum 3. In any event, the velocities must be accurately adapted to each other, so that during each revolution of the drum the cutting attached to the disk 9 exactly enters into the individual grooves. The spacing of the individual grooves 13 in the sieve drum shell 3' depends on the required staple lengthS. The minimum staple length is determined by the distance of the iridividual grooves from one another; whereas the maximum staple length depends merely on the ratio of the rotational speeds. Thus, it is readily possible to leave out one or more grooves during each cutting operation, which makes it possible to produce also greater staple lengths without exchanging the individual elements of the apparatus.

FIGS. 4 and 5 show two differently constructed sieve drums 3; the drum of FIG. 4 has a shell surface aligned in parallel to the drum axis; whereas the shell surface according to FIG. 5 is curved in a concave manner. This concave configuration of the sieve drum shell surface makes it possible to offer an always uniform depth of penetration into the groove 13 for the path of movement of the blade, illustrated in dot-dash lines. In this connection, the groove 13 can be milled into the shell surface or-as shown in FIG. 4the groove can be formed by a gap between strips forming the shell of the sieve drum.

The cutting disk 9, illustrated only schematically in FIG. 1, is shown in greater detail in FIGS. 6 through 9 with different embodiments. The blade can be fashioned as an endless (i.e. continuous) or as an intermittent knife. In case of an endless blade, this blade must form either a spiral or helical curve. In case of a spiral shape, as shown in FIG. 8, the blade extends in a plane, whereas, in case of a helical extension of the blade, as shown in FIG. 9, a type of worm wheel is required for the production of the staples.

In case the blade is discontinuous, a cut through the cable can be executed with each of the cutting means 14 and shown in FIGS. 6 and 7, respectively; whereas, in the embodiment of FIG. 8, each rotation of the disk executes one cutting step. The blades according to FIGS. 6 and 7 are formed by cutting elements or means individually attached to the disk. According to FIG. 6, these elements can be, for example, razor blades 14; whereas according to FIG. 7 additional cutting disks 15 are provided which are mounted in the support disk 9 in a rotatable and optionally also in a driven manner. In case of the rotating cutting disks 15, the portion of the disks 15 which comes into contact with the cable to be cut changes automatically with each cutting step, so that the small disks 15 are worn off uniformly along their circumference. Also, the curvature along the blade, necessary to effect an easier cutting operation, is provided by the configuration of the cutting disks 15, whereas this feature is obtained in case of the elements 14 only due to their oblique positioning in the support disk 9.

The cutting device or apparatus according to FIG. 10 is similar to that of FIG. 1. The cable 1, fed from a different direction, is cleanly cut through on the drum 3 by the rotating disk, shown in dot-dash lines. The drum, instead of being a sieve drum with slots 13, can also consist of a slotted drum 3 according to FIG. 1]. In the device according to FIGS. 10 and 12, the inner cover l2otherwise, an outer cover 12' is providedreaches directly to the cutting point. In this way, the cable transported by the drum 3 is no longer held at the cutting point on both sides by the suction draft ambient within the drum. The drum 3 is effective as a conveying element with its suction draft only above the cutting point. In contrast thereto, a duct 17 is disposed below, the suction opening of which extends up to directly beneath the cutting point and has a sealing action with respect to the surface of the drum 3', on the other end of this duct, a fan 18 is provided for the production of a strong suction draft. In this way, the effect is obtained which can be seen from FIG. 12: by the suction draft of fan 18, the free end 1 of the crimped tow l is sucked into the suction opening of the duct 17 and tightly stretched at the cutting point against the holding force of the drum 3. This makes it possible to cleanly cut also texturized material without any difficulties by the rotating blades of the cutting device 9.

The holding device 19 serves as a further auxiliary measure for the prevention of a blowing about of fiber layers or the blowing away of fibers not in direct contact with the drum 3 and thus not retained by the suction draft within the drum; this holding device is fashioned as a resilient plate and presses, under tension, against the cable 1 held by the suction draft onto the drum 3. The free end of the spring 19 is disposed directly above the blades, so that the cable conveyed by the drum 3 is retained on both sides of the cutting point. It is now no longer possible for the fibers to be shifted in the direction of the rotating knives, and no eddies of air can become effective, for example, by the rotation of the cutting blades; such eddies are substantially prevented by the unit 20 encompassing the cutting device. The two, conveyed by the drum 3 to the cutting point is seized, directly after the suction draft has been eliminated by the cover 12, by the suction draft at the mouth of the suction duct 17 and is conveyed into the duct. Only thereafter is the cable cut by the rotating knives or cutting elements.

The device of FIG. 13 is similar to that of FIG. 10. The detail encircled in this figure will be described and explained hereinbelow.

In this embodiment, the cutting blades are formed by cutting plates or leaves 15, disposed at regular intervals along the periphery of the cutting disk 9 and being rotatably mounted about a pin 21. In order to ensure a uniform rotation of the cutting plates 15, they are held between two bearing disks 22 of bearing metal. The metal can be self-lubricating, but it is also possible to provide the bearing disks with lubricating points oriented toward the cutting plate 15. By means of a spring ring 23, held by a Seeger ring 24, the respective cutting plate 15 is held under tension at the cutting disk 9. When the cutting plate 15 cuts through the tow lying on the sieve drum 3, the cutting plate 15, due to the thus-occurring friction between the tow I and the blade, will rotate about the pin 21even if only by a few millimetersso that, at the subsequent cutting step, the plate 15 contacts the tow with a different cutting edge. The rotation of the plate can also be effected in a controlled fashion by special means so that, upon each cutting step, the plate is rotated by a specific amount. For this purpose, a motor can be provided.

In order to ensure a long service life of the cutting plates 15, particularly uniform sharpness of the blade, each cutting plate 15 is associated with sharpening devices which sharpen the plate either unilaterally or bilaterally along the edge during the operation of the cable cutting device.

The sharpening devices can be of varying types. According to FIG. 14, grinding lamellae 25 are attached to the device 20 surrounding the cutting disk 9. This device 20 serves for the prevention of air currents which could unduly shift or lift the cable disposed on the sieve druin 3. The sharpening lamellae 25 are aligned obliquely with respect to the alignment of the cutting plates or leaves, namely in parallel to the associated cutting surface. Furthermore, the grinding lamellae 25 are disposed so that they are offset with respect to one another, so that first the topside of the plates and then the underside of the plates are sharpened. In this arrangement of the sharpening lamellae 25, a high relative speed exists which causes an effi' cient sharpening of the plates 15.

In case such high relative speeds are unnecessary for a sufficient sharpening action, the grinding device can also be attached to the cutting disk 9. One embodiment thereof is shown in FIG. 15 in connection with FIGS.

16 and 17. In this construction, grinding lamellae 26 are mounted to strips 27 of spring steel by means of bolts 28 at the cutting disk 9 The grinding lamellae 26 likewise contact alternatingly the topside and the underside of the respective cutting plate 15, so that a sharpening of the plate takes place on both sides. However, depending on the configuration of the plate, a one-sided grinding operation can be sufficient. Of course, the sharpening lamellae 25 or,26 can also be replaced by grinding rings or segments thereof. Also, a grinding ring can be fixedly arranged concentrically about the axis of the cutting disk 9, or such ring can be driven, so that the relative speed between the cutting plates and the grinding surface can be influenced. However, in most cases, the movement of the plates alone due to the friction of the cable during the cutting step will be sufficient to effect sharpening, since the cuts take place continuously at a high rate.

While the novel embodiments of the invention have been described, it will be understood that various omissions, modifications and changes in these embodiments maybe made by one skilled in the art without departing from the spirit and scope of the invention.

1 claim:

1. A device for cutting endless fibrous materials, particularly for the production of staple fibers from synthetic fibrous material, which comprises a rotatably mounted support means, including drum means subjected to a suction draft, for feeding endless fibrous material to a cutting zone, and a rotatably mounted cutting means operatively associated with said drum means for cutting the fibrous material into staple length in said cutting zone; said drum means 'comprising a drum having an outer shell provided with an air permeable surface for retaining said fibrous material thereon by said suction draft and having an axis arranged at a spaced distance from and at right angles to an axis of rotation of said cutting means, said cutting means including a rotating disk having at least one cutting blade at its outer circumference for cutting through the fibrous material retained on said surface of the drum and said outer shell having means for preventing said at least one blade from contacting the surface of the outer shell during cutting of said fibrous material.

2. The device of claim 1, in which the rotating disk has an endless cutting blade.

3. The device of claim 1, in which the cutting blade has a cutting edge curved in a convex manner.

4. The device of claim 1, in which a plurality of cutting blades are arranged discontinuously about the circumference of said rotating disk.

5. The device of claim 4, in which each cutting blade comprises a circular cutting disk smaller as compared to the rotating disk, these cutting disks being mounted on the outer periphery of the rotating disk in a rotatable manner, optionally in a driven manner.

6. The device of claim 4, in which each cutting blade is fashioned to be straight, but is aligned at an angle obliquely with respect to the tangent at the mounting point of this blade at the rotating disk.

7. The device of claim 4, in which each blade is attached at the rotating disk in an exchangeable manner.

8. The device of claim 2, in which the cutting means includes a worm wheel with at least one flight, a cutting edge being provided on said flights.

9. The device of claim 2, in which the cutting means includes a spirally extending cutting blade.

10. The device of claim 1, in which said drum means has an outer air-permeable shell with a surface curved in a concave mariner.

11. The device of claim 1, in which said drum means includes a drum that has an outer cylindrical shell, said shell being provided with grooves aligned obliquely with respect to the axis of the drum and spaced to determine the minimum staple length.

12. The device of claim 11, in which the grooves are milled into the shellof the drum.

13. The device of claim 11, in which the drum shell is formed by perforated sheet metal strips of a width approximately corresponding to the staple length.

14. The device of claim 1, in which said drum means includes fan means for producing said' suction draft, said device further including means so that the airdrawn by the fan means through the shell surface of the drum for retaining the fibrous material is at least partially conducted to the cutting zone in order to discharge the cut fibrous material.

15. The device of claim 14, in which a spiral housing surrounding the fan means extends, with its outlet duct, up to the cutting zone, thereby providing a staple fiber conveying duct.

16. The device of claim 15, in which said drum is a sieve drum covered by a cover along the portion of the shell not occupied by the fibrous material and the exhaust air of the fan means is conducted through a conduit into the space between the cover and the shell of the drum.

17. The device of claim 1, further comprising guide means forcing the fibrous material tautly stretched in the longitudinal direction on a drum of said drum means and engaging the material at least at the cutting zone.

18. The device of claim 17, in which the guide means includes a spring pressing from the outside against the material and thus against the drum.

19. The device of claim 18, in which the spring is disposed on the side of the drum covered by the material and approximately tangentially with respect to the drum at the cutting zone.

20. The device of claim 18, in which the free end of the spring extends directly up to the cutting zone.

21. The device of claim 17, further comprising a suction device discharging the cut fibrous material on the half of the drum not covered by the material on the other side with respect to the cutting means, a cover associated with the drum is extended up to the level of the cutting zone; and a suction nozzle is arranged directly beyond the rotating cutting means.

22. The device of claim 21, in which said drum is provided with cutting slots, said cutting slot being covered against the suction draft from the drum by said cover.

23. The device of claim 22, in which the suction nozzle terminates in the direct vicinity of the drum.

24. The device of claim 21', in which the end of the fibrous material to be cut is held in a tautly stretched condition atthe cutting zone, on the one hand by the drum under a suction draft, and on the other hand by the suction draft of the suction nozzle.

25. The device of claim 5, in which a sharpening device is operatively associated with the blade of each of the cutting plates, said sharpening device engages the blade to sharpen the blade during rotation thereof.

26. The device of claim 25, in which the sharpening device is disposed adjacent the rotating disk.

27. The device of claim 26, in which the sharpening device is fixedly mounted to the rotating disk.

28. The device of claim 27, in which the sharpening device is disposed on the rotating disk to be movable relatively to the rotating cutting plate.

29. The device of claim 28, in which the sharpening device is arranged separately from the cutting rotating disk in a fixed manner, at a member encompassing the rotating disk.

30. The device of claim 25, in which the sharpening device consists of grinding means engaging the blade of the cutting plates on at least one side.

31. The device of claim 28, in which the relative motion between the cutting plates and the sharpening device including the concentric circular movement of the cutting plates is caused by the friction of the blade at the fibrous material upon each cut through said material.

32. The device of claim 31, in which the cutting plates are held on both sides in a rotatable manner by means of preferably self-lubricating bearings.

33. The device of claim 32, in which the bearings are made of non-ferrous metal.

34. The device of claim 32, in which the bearings are disposed resiliently with respect to the cutting plate.

35. The device of claim 25, in which the sharpening device contacts the blade of the cutting plates with a slight pressure, especially in a resilient manner.

36. The device of claim 34, in which the sharpening device is mounted at a holder made of a material which is resilient with respect to the cutting plates.

37. The device of claim 1, in which said means for preventing contact between the surface of the outer shell and said at least one cutting blade comprises means defining a plurality of parallel grooves on said outer shell, said grooves being spaced from each other to determine the minimum staple length and to allow successive entry of said at least one cutting blade therein during cutting of said fibrous material.

38. The device of claim 1, in which the outer shell of said drum is so arranged adjacent to said cutting means that the suction draft retains the fibrous material on said surface of said drum at said cutting zone.

39. The device of claim 38, in which said drum is provided with an inner cover for preventing application of said suction draft to a portion of said outer shell, said cover being so arranged that the fibrous material is retained by said suction draft on at least one side of a cut made by said cutting means.

40. The device of claim 1, in which the axis of said drum is disposed horizontally and the axis of said cutting means is disposed vertically.

41. A device for cutting endless fibrous material, particularly for the production of staples from synthetic fibers, which comprises a rotatably disposed support means for feeding the fibrous material to a cutting zone, said support means including drum means subjected to a suction draft; a rotatably mounted cutting means operatively associated with said drum means for cutting said fibrous material in said cutting zone; said drum means including a sieve drum having an outer shell and fan means for producing said suction draft; means operatively associated with said drum means so that the air drawn by the fan means through the shell surface of the drum for retaining the fibrous material thereon is at least partially conducted to the cutting zone in order to discharge the cut fibrous material; and a spiral housing surrounding the fan means extending, with its outlet duct, up to the cutting zone to thereby provide a staple fiber conveying duct, said sieve drum being covered by a cover along a portion of the shell not occupied by the fibrous material and exhaust air of the fan means being conducted through a conduit into the space between the cover and the shell of the drum. 

1. A device for cutting endless fibrous materials, particularly for the production of staple fibers from synthetic fibrous material, which comprises a rotatably mounted support means, including drum means subjected to a suction draft, for feeding endless fibrous material to a cutting zone, and a rotatably mounted cutting means operatively associated with said drum means for cutting the fibrous material into staple length in said cutting zone; said drum means comprising a drum having an outer shell provided with an air permeable surface for retaining said fibrous material thereon by said suction draft and having an axis arranged at a spaced distance from and at right angles to an axis of rotation of said cutting means, said cutting means including a rotating disk having at least one cutting blade at its outer circumference for cutting through the fibrous material retained on said surface of the drum and said outer shell having means for preventing said at least one blade from contacting the surface of the outer shell during cutting of said fibrous material.
 2. The device of claim 1, in which the rotating disk has an endless cutting blade.
 3. The device of claim 1, in which the cutting blade has a cutting edge curved in a convex manner.
 4. The device of claim 1, in which a plurality of cutting blades are arranged discontinuously about the circumference of said rotating disk.
 5. The device of claim 4, in which each cutting blade comprises a circular cutting disk smaller as compared to the rotating disk, these cutting disks being mounted on the outer periphery of the rotating disk in a rotatable manner, optionally in a driven manner.
 6. The device of claim 4, in which each cutting blade is fashiOned to be straight, but is aligned at an angle obliquely with respect to the tangent at the mounting point of this blade at the rotating disk.
 7. The device of claim 4, in which each blade is attached at the rotating disk in an exchangeable manner.
 8. The device of claim 2, in which the cutting means includes a worm wheel with at least one flight, a cutting edge being provided on said flights.
 9. The device of claim 2, in which the cutting means includes a spirally extending cutting blade.
 10. The device of claim 1, in which said drum means has an outer air-permeable shell with a surface curved in a concave manner.
 11. The device of claim 1, in which said drum means includes a drum that has an outer cylindrical shell, said shell being provided with grooves aligned obliquely with respect to the axis of the drum and spaced to determine the minimum staple length.
 12. The device of claim 11, in which the grooves are milled into the shell of the drum.
 13. The device of claim 11, in which the drum shell is formed by perforated sheet metal strips of a width approximately corresponding to the staple length.
 14. The device of claim 1, in which said drum means includes fan means for producing said suction draft, said device further including means so that the air drawn by the fan means through the shell surface of the drum for retaining the fibrous material is at least partially conducted to the cutting zone in order to discharge the cut fibrous material.
 15. The device of claim 14, in which a spiral housing surrounding the fan means extends, with its outlet duct, up to the cutting zone, thereby providing a staple fiber conveying duct.
 16. The device of claim 15, in which said drum is a sieve drum covered by a cover along the portion of the shell not occupied by the fibrous material and the exhaust air of the fan means is conducted through a conduit into the space between the cover and the shell of the drum.
 17. The device of claim 1, further comprising guide means forcing the fibrous material tautly stretched in the longitudinal direction on a drum of said drum means and engaging the material at least at the cutting zone.
 18. The device of claim 17, in which the guide means includes a spring pressing from the outside against the material and thus against the drum.
 19. The device of claim 18, in which the spring is disposed on the side of the drum covered by the material and approximately tangentially with respect to the drum at the cutting zone.
 20. The device of claim 18, in which the free end of the spring extends directly up to the cutting zone.
 21. The device of claim 17, further comprising a suction device discharging the cut fibrous material on the half of the drum not covered by the material on the other side with respect to the cutting means, a cover associated with the drum is extended up to the level of the cutting zone; and a suction nozzle is arranged directly beyond the rotating cutting means.
 22. The device of claim 21, in which said drum is provided with cutting slots, said cutting slot being covered against the suction draft from the drum by said cover.
 23. The device of claim 22, in which the suction nozzle terminates in the direct vicinity of the drum.
 24. The device of claim 21, in which the end of the fibrous material to be cut is held in a tautly stretched condition at the cutting zone, on the one hand by the drum under a suction draft, and on the other hand by the suction draft of the suction nozzle.
 25. The device of claim 5, in which a sharpening device is operatively associated with the blade of each of the cutting plates, said sharpening device engages the blade to sharpen the blade during rotation thereof.
 26. The device of claim 25, in which the sharpening device is disposed adjacent the rotating disk.
 27. The device of claim 26, in which the sharpening device is fixedly mounted to the rotating disk.
 28. The device of claim 27, in which the sharpening device is disposed on the rotating disk to be movable relatively to the rotating cutting plate.
 29. The device of claim 28, in which the sharpening device is arranged separately from the cutting rotating disk in a fixed manner, at a member encompassing the rotating disk.
 30. The device of claim 25, in which the sharpening device consists of grinding means engaging the blade of the cutting plates on at least one side.
 31. The device of claim 28, in which the relative motion between the cutting plates and the sharpening device including the concentric circular movement of the cutting plates is caused by the friction of the blade at the fibrous material upon each cut through said material.
 32. The device of claim 31, in which the cutting plates are held on both sides in a rotatable manner by means of preferably self-lubricating bearings.
 33. The device of claim 32, in which the bearings are made of non-ferrous metal.
 34. The device of claim 32, in which the bearings are disposed resiliently with respect to the cutting plate.
 35. The device of claim 25, in which the sharpening device contacts the blade of the cutting plates with a slight pressure, especially in a resilient manner.
 36. The device of claim 34, in which the sharpening device is mounted at a holder made of a material which is resilient with respect to the cutting plates.
 37. The device of claim 1, in which said means for preventing contact between the surface of the outer shell and said at least one cutting blade comprises means defining a plurality of parallel grooves on said outer shell, said grooves being spaced from each other to determine the minimum staple length and to allow successive entry of said at least one cutting blade therein during cutting of said fibrous material.
 38. The device of claim 1, in which the outer shell of said drum is so arranged adjacent to said cutting means that the suction draft retains the fibrous material on said surface of said drum at said cutting zone.
 39. The device of claim 38, in which said drum is provided with an inner cover for preventing application of said suction draft to a portion of said outer shell, said cover being so arranged that the fibrous material is retained by said suction draft on at least one side of a cut made by said cutting means.
 40. The device of claim 1, in which the axis of said drum is disposed horizontally and the axis of said cutting means is disposed vertically.
 41. A device for cutting endless fibrous material, particularly for the production of staples from synthetic fibers, which comprises a rotatably disposed support means for feeding the fibrous material to a cutting zone, said support means including drum means subjected to a suction draft; a rotatably mounted cutting means operatively associated with said drum means for cutting said fibrous material in said cutting zone; said drum means including a sieve drum having an outer shell and fan means for producing said suction draft; means operatively associated with said drum means so that the air drawn by the fan means through the shell surface of the drum for retaining the fibrous material thereon is at least partially conducted to the cutting zone in order to discharge the cut fibrous material; and a spiral housing surrounding the fan means extending, with its outlet duct, up to the cutting zone to thereby provide a staple fiber conveying duct, said sieve drum being covered by a cover along a portion of the shell not occupied by the fibrous material and exhaust air of the fan means being conducted through a conduit into the space between the cover and the shell of the drum. 